Alcohol-induced aggression is a serious problem with serious, far-reaching consequences for individual and public health. The proposed study is expected to contribute new evidence to the existing body of knowledge of ethanol-heightened and other forms of escalated aggression. The project will examine individual differences in ethanol self-administration, vulnerability to ethanol-induced aggression, aggression following social-instigation, and escalated aggression following extinction of scheduled reinforcement. The research will utilize an animal model (i.e. mice), well-established ethanol self-administration techniques, the resident intruder paradigm, and detailed behavioral analyses. Escalated aggression may be due to interactions of GABA and 5-HT in mesocorticolimbic neurons. Therefore, the present project will investigate the role played select neurotransmitter systems, specifically GABA and 5-HT, in escalated aggression employing pharmaceutical receptor manipulations to determine if neurotransmitter systems play a predictive role in [modulating such behaviors. Thus, the present research should enhance current understanding of individual characteristics and neurochemical mechanisms involved in alcohol-heightened aggression. [unreadable] [unreadable]